This invention relates to a coordinated lift system. In particular, this invention relates to a coordinated lift system having at least two lift mechanisms that communicate by signals carried by cables to coordinate the raising and lowering of a vehicle.
The need to lift a vehicle from the ground for service work is well established. For instance, it is often necessary to lift a vehicle for oil changes, brake inspections, exhaust work and other automotive maintenance. Traditionally, lifting a vehicle has been accomplished through the use of equipment that is built-in to the service facility. These built-in units are located at a fixed location at the service facility and adapted to contact the vehicle frame to lift the vehicle from the ground. However, built-in units are very expensive and sometimes impractical due to their lack of mobility.
To increase mobility and reduce the need to invest in permanent lifting equipment, a device commonly known as a mobile lift column was developed. Mobile lift columns are available from the owner of this invention, Ari-Hetra, www.ARI-HETRA.com. A set of mobile lift columns is typically used to independently engage each of the tires and lift the vehicle from the ground. To lift a vehicle in a generally level orientation with independent lift columns, a user must go back and forth between each lift column to incrementally raise each lift until the vehicle reaches the desired height or involve several people. While this type of lifting column is less expensive and provides more mobility than the built-in units, using a number of independent lift columns to lift the vehicle is a time consuming and tedious process.
Another type of system 1 for lifting a vehicle 3 using multiple lifting columns 5 is shown in FIG. 3 and includes a number of cables or wires 7 to connect the lifting columns 5 to one another. The cables or wires 7 that are connected between the columns 5 allow the vehicle 3 to be raised or lowered in a uniform fashion. However, this system 1 also suffers from a number of drawbacks and deficiencies. For instance, the cables and wires 7 used to connect the individual columns extend across the floor 9 and are looped within the working area. The presence of the cables and lines 7 on the ground in the work area poses a tripping hazard to people working near the vehicle 3. Vehicles also often drive over these connecting cables 7 causing damage.
Some newer lifting systems utilize wireless communication among the individual lifting columns to coordinate their operation. However, such wireless systems are not an option in many cases due to the added cost of purchasing an entire set of lifting columns equipped with wireless communication capabilities. Many users are not willing to replace sets of existing and operational lift columns, but wish to alleviate the tripping and other hazards associated with the network of cables connecting the lifting columns.
Accordingly, there remains a need for a mobile lift system that is able to coordinate the raising or lowering of a vehicle with cables connecting the individual lift columns while avoiding the tripping and other hazards of such systems. This invention satisfies these and other needs.